Re: [Geotools-devel] more cts debugging help

[Martin D. <mar...@te...>]

Hello Rueben

Rueben Schulz a =E9crit:
> Attached is my copy of Simple_TestScript with the tests I did for the
> datum shifts. Feel free to include this with the cts testing. I also
> have a transverse mercator test that failed, but will leave that out
> until I am working on that projection.=20

Wonderful!!! I will commit this Simple_TestScript today and lets peoples=20
know when it will be done. Many thanks for all yours work!




> 1) where is the best place to put constants shared by mercator and the
> spheroid inner class. Right now I have 2 copies of them, because I
> cannot think of a better way.

Mercator is the right place. Just declare it 'protected' instead of=20
'private' and remove the declaration in the 'Spherical' inner class. Add=20
the following constructor to 'Mercator':


/**
  * Construct a Mercator projection with an explicit {@link #ak0}
  * parameter. This constructor is used for the initialisation of
  * spherical projection only.
  */
private Mercator(final Projection parameters, final double ak0) throws=20
MissingParameterException {
     super(parameters);
     this.ak0 =3D ak0;
}



The 'Spherical' constructor will then become:

protected Spherical(final Projection parameters) throws=20
MissingParameterException {
     super(parameters, scaleFactor * semiMajor*Math.cos(latitudeTrueScale=
));
}


I removed the Math.abs(latitudeTrueScale) call since this formula use=20
'latitudeTrueScale' in Math.cos(...) only, and cos(theta) =3D=3D cos(-the=
ta).





> 2)should the 2SP mercator case be handled separately, the way it is for
> Lambert? Right now this class handles both 1SP and 2SP cases.=20

Maybe. I have to admit that I have not looked deeply to the formulas for=20
1SP. What are the differences in the formulas?



> 3)does the Sphere inner class need to override Provider as well, and
> will this require a new provider to be listed in MathTransformFactory t=
o
> use it?

No. Instead, the existing Provider need to be updated. Replace the=20
following line in the 'create' method:

     return new Mercator(parameters);

By:

     if (isSpherical(parameters)) {
         return new Spherical(parameters);
     } else {
         return new Mercator(parameters);
     }


I will commit the 'isSpherical(Projection)' convenience method in a few=20
minutes (right now it doesn't exists).



> I will start on Lambert once I get these issues and a bit more testing
> done.


Great!!!

	Martin.